1. Field of the Invention
The present invention relates to a coil device used as a pulse transformer or so, and more specifically the present invention relates to the coil device suitably used for a surface mounting.
2. Description of the Related Art
Many coil devices as an inductor element and a transformer or so are mounted on various electronic-electric equipment. In addition to making the size of the coil device itself compact, in order to correspond to the compact electronic devices of recent years, such coil devices are further demanded to be capable of mounting on the surface and to have good uniformity with little production variation enabling the high density mounting. As the problem to be improved from such point of view, for example the reduced surface mounting property of the coil device may be mentioned, which is caused by the formation of the alloy layer (the reaction product between the core material of the wire and the plating formed to the terminals or so) deteriorating the wettability against the solder when fixing the wire to the terminal during the coil device production steps.
As the conventional art which corresponded to such problem, the technology of forming the plurality of the surfaces having steps at the terminals are proposed thereby providing the surface to which the alloy layer can be rarely formed (see Patent document 1).
[Patent document 1] JP Patent Application Laid Open No. 2013-191694